Create a lesson based off the article ‘A Paleo Perspective on Global Warming’.? Lesson is based off questions that need to answered under: ‘Decision-Making Questions and Statements’APale

The first decade of the 21st century was the warmest of the entire global instrumental temperature record, starting in the late-19th century. The 14 years from 2000 to 2013 rank among the 18 warmest, which makes these high temperatures unusual over the period of instrumental measurements. But, what about in the context of past centuries or millennia? How unusual are modern temperatures compared to those of the past? It is only through the reconstruction of past climate that we can truly evaluate the magnitude of this warming.

When one reviews all the data, both from thermometers and paleoclimate temperature proxies, it becomes clear that Earth has warmed significantly since the late 19th century. Global warming has occurred. Multiple paleoclimatic studies indicate that recent years are all the warmest, on a global basis, of at least the last 1,000 years. The most recent paleoclimate data reinforce this conclusion using longer records, new proxies, new statistical techniques, and a broader geographic distribution. There are, however, questions remaining concerning global warming. For instance, what are the implications for the future? The answers to these questions are not simple.

Most climate scientists have come to the conclusion that human activity is causing the climate to change. First on the list of likely human influences is warming due to increasing concentrations of greenhouse gases in the atmosphere. Other human activities are thought to drive climate as well. As ice core data show, the increase in carbon dioxide is unprecedented and well outside the range of natural variations. The recent increase matches the increase calculated from the fossil fuel emissions. There is little doubt that these gases will contribute to global warming, and here too the paleoclimate record provides invaluable evidence regarding how much temperature change accompanied changes in carbon dioxide over the past several hundred thousand years. However, there is uncertainty about some issues. For example, these questions remain to be answered with complete confidence:

· How much warming has occurred due to anthropogenic increases in atmospheric trace-gas levels?

· How much warming will occur in the future?

· What other changes will occur with future warming?

Paleoclimatology offers help in answering each of these questions. Several of the paleoclimate studies reported in this web document have begun efforts to attribute past climate change to both natural and human causes, and to estimate how much of the current warming is due to humans (i.e., greenhouse warming). The best estimate is that more than 50% of the observed global warming is due to greenhouse gas increases.

The paleoclimate record also tells us how much temperature change occurred in the past when carbon dioxide levels were different. Studies show that the 100 ppm reduction in carbon dioxide during the last glacial period was accompanied by a ~1.5°C cooling in the tropical oceans (MARGO project members 2009). This amount of temperature change is consistent with the change predicted by numerical climate model simulations. Changes at higher latitudes were much larger and included the growth of large ice sheets. Other studies of the glacial world show that many aspects of climate were different when carbon dioxide was reduced, including lower sea level, lower snow lines, and altered patterns of circulation. Based on these studies we can predict that other aspects of the climate in addition to temperature are likely to change with future warming.

Abrupt Climate Change: A Paleo Perspective

Imagine that over the course of a decade or two, the long, snowy winters of northern New England were replaced by the milder winters of a place like Washington, D.C. Or that a sharp decrease in rainfall turned the short-grass prairie of the western Great Plains into a desert landscape like you would see in Arizona. Changes of this sort would obviously have important impacts on humans, affecting the crops we grow, the availability of water, and our energy usage.

These scenarios are not science fiction. Paleoclimate records indicate that climate changes of this size and speed have occurred at many times in the past. Past human civilizations were sometimes successful in adapting to the climate changes and at other times, they were not.

Abrupt climate change is climate change that occurs relatively rapidly. Our understanding of past abrupt climate changes and their causes is still in its infancy; most of the research on this topic has occurred since the early 1990s. Scientists have made significant progress, however, in identifying and describing various abrupt events of the past and forming hypotheses about their causes. One of the most remarkable aspects of this history is the diversity of past climate change. Events varied in their duration, rapidity, spatial extent, and climate impacts. This testifies to the many nonlinear processes, thresholds, and interactions that exist in our complex climate system. This Paleo Perspective highlights some of the most important events that paleoclimate records have illustrated.

Decision-Making Questions and Statements

General Issues

Public Policy

Should governments be allowed to operate against environmental regulation laws?

Moral-Value Issues

Is ethically acceptable to deny global climate change and possible causes for it?

Definitional Issues

What is the meaning of anthropogenic global climate change? What is the meaning of adaptation?

Factual Issues

If the science can prove human activity as an impact on global climate change, then would there be an increase in worldwide environmental regulation laws?

Prescriptive Issues

Personal Conviction and Conscience

What would you do if you were a member of a governing body and you had to make a choice to vote for or against environmental protection laws?

Public Policy

Should the government make any exceptions for the multibillion dollar corporations involved in oil refinement?

Ethics

Ultimately, which is more important – saving the planet and all whom inhabit it or profiting from the continued exploitation of its natural resources?

Law

Would an international regulation on environmental protection laws improve the overall progress in individual nations?

Descriptive Issues

Casual Claims

Anthropogenic global climate change can explain the increase in CO2 in the atmosphere.

Associative Claims

Even if there is an increase in CO2, the increase has no impact on the climate since there is no convincing evidence of warming.

Interpretive or Speculative Claims

It is acceptable to continue to disregard environmental safety warnings in the United States, but not in other countries; rejecting the theory of global climate change has proven to be favorable among Americans.